Behavior of oxygen bubbles during crystal growth of Ca12Al14O33 by floating method in magnetic field by J. K. Park, T. Shimomura, M. Yamanaka, S. Watauchi, K. Kishio, and I. Tanaka

Crystal Research and Technology

Cryst. Res. Technol. 40, 329 (2005) - Abstract -

Behavior of oxygen bubbles during crystal growth of Ca₁₂Al₁₄O₃₃ by floating method in magnetic field

J. K. Park, T. Shimomura, M. Yamanaka, S. Watauchi, K. Kishio*, and I. Tanaka

Center for Crystal Science and Technology, University of Yamanashi, 7 Miyamae, Kofu, Yamanashi 400-8511, Japan
*Department of Superconductivity, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

Keywords	magnetic field, magnetic force, calcium aluminate, floating zone
PACS	81.10.Fq, 83.60.Np, 81.10.-h, 75.70.kw
DOI	10.1002/crat.200410346

Magnetic field generator using a helium-free superconducting magnet was installed with an infrared light heating floating zone (FZ) apparatus. Single crystals of Ca₁₂Al₁₄O₃₃, in which oxygen bubbles easily remain when it is grown by a conventional FZ, were grown in various magnetic conditions in order to investigate the behavior of oxygen bubbles in molten zone, and to research the magnetic effects on FZ growth. When the crystals were grown at the lower position than center of the magnet bore, where magnetic force to paramagnetic oxygen gas is upward, oxygen bubbles formed in the molten zone were inclined to go toward stronger field and the grown crystals were half transparent and half opaque. The distribution of remaining oxygen bubbles in crystals was rather lopsided than centered. These effects might be explained by the magnetic force effect and the magnetic convection effect driven by inhomogeneous heating of the melt.

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